Stomach and intestine of an living body often bleed due to various diseases, accidents or damages caused by endoscopic treatment. As to active bleeding, it is usually treated by drug spraying, high-frequency electricity, laser, argon burning method of the bleeding site, or mechanical compression hemostasis method using hemostatic clamp. The mechanical compression hemostatic method using hemostatic clip is most reliable for treating non-variceal active bleeding, and is accepted by doctors and patients. As traditional clinical operation is more invasive, mucosa of the digestive tract is further damaged. Using clamp for closure of the mucosal wound of the digestive tract can spur healing, and also achieve effective closure of small perforation of the digestive tract, the effect of which is now accepted in clinical practice. This method can minimize the damage to the patient brought by laparotomy.
Japanese patents laid-open No. 2002-196909 and laid-open No. 2004-121485 disclose a clamping device for ligation of biological tissue, which comprises an insertion unit, a clamp unit, and a clamp operation unit. The insertion unit can be inserted into the endoscope channel which has been inserted into a body cavity of the living body; the clamping unit can be mounted on the top of the insertion unit detachably with respect to the top of the insertion unit, and includes a clamp; the clamp operation unit comprises an operation subunit which is exposed from the bottom of the insertion unit, a connection subunit which is not connected with the clamping unit and which cannot extend to the top of the insertion unit when operating from the outside, and a clamp which can use the operation subunit to open or close the clamping unit. The clamping unit has a connection structure, which can be operated by the clamp operation unit to move along the extending direction through the passage of the clamp. The connection structure has a break portion, which can be broken when the pulling force on the clamp operation unit is over a certain range. The connection structure is formed by injection molding a high-strength resin material such as liquid crystal polymer or nylon. One part of the outer peripheral surface of the break portion has a cut, which is formed in a radial direction and extends in a direction intersecting the moving direction of the clamp. Besides, the other ends of a plurality of elongate arms of the clamp which are connected to one another are locked in the cut.
In the patents above, the connection structure is made of polymer materials. Since the digestive tract is curved, the channel of the endoscope needs to be bended to reach the lesion location, especially in some special location, the channel of the endoscope needs to be bended to the limit to reach the lesion, thus the ligation device running through the channel of the endoscope also needs to be bended, which causes damage or strength degradation of the connection structure. This makes release of the clamp become difficult or even causes the clamping unit to fail and results in operation delay. Furthermore, the proximal end of the connection structure is connected with the clamp operation unit and is exposed to the outside of the holding structure, thus the clamping unit is too long to pass the channel of the endoscope, especially when the endoscope needs to be bended to a greater extent, it may be even harder for the ligation device to pass the channel of the endoscope to reach the lesion location for effective clamping. In this situation, the doctor needs to adjust the bending amplitude to make the clamping unit exposed to the outside of the channel of the endoscope. However, the lesion location will not be able to be observed by the endoscope for a period of time, which may cause risks, especially when the patient is bleeding heavily.
Therefore, a clamp device is in urgent need which can easily pass the channel of the endoscope to reach the lesion location and can be well released.